Spring cleaning with multiarch support

[amotl]

Hi there,

along the lines of #113, @bogde and @el3ctrician approved the idea of a spring cleaning of this library.

So, we would like to share what we have now: Different pieces of code and suggestions from various people have been incorporated, I will try to add references to the relevant issues on behalf of the next comment to keep this introduction shorter.

As I don't actually have any hardware on my workbench, I am humbly asking the community (all of you ;]) about whether you would like to give the revamped library a testdrive on a real iron? I will be happy to receive any feedback about the outcome.

While we are discussing this topic at [1], the work-in-progress branch is located at [2] and might receive further updates as we go. We hope you like it.

With kind regards,
Andreas.

[1] https://community.hiveeyes.org/t/improving-the-canonical-hx711-library-for-arduino/539
[2] https://github.com/hiveeyes/HX711/tree/spring-cleaning

[amotl]

This actually bundles many suggestions floating around here since quite some time. We hope to have assembled them carefully into something which will be more useful for the community again by making people struggle less when starting with this library on more contemporary and powerful MCUs like ESP, SAMD, STM32 and others.

This branch directly incorporates

parts from these pull requests, selected by cherry-picking.

• AVR interrupt safety, see Prevent ints from corrupting the read sequence #62
• ESP32 support, see ESP32 issue, clock speed too fast #75
• Teensy 3.x support, see Added 2 examples (basic use and timeouts) and support for Teensy 3.2 #96

Also, it will probably contain different bits and pieces from issue requests which have not been pulled in using PRs. We tried our best to knit everything together well. Thanks a bunch for your contributions!

and also

most probably addresses all issues people are having with

ESP8266 arch pragma / yield definition woes

• esp32 multiple definition of `yield' #114 and WiFiSecureClient crashes during connection #119

ESP8266 constructor initialization freezes

• Include begin procedure and change object constructor code #29, Fixing #29, Travis CI integration and ESP8266 Fixes #40, Reflect issue #29 within the docs #53, Does this library works with arduino due #89, more stability for ESP8266 #113, Update example file HX711ESP8266.ino #122

ESP8266 watchdog timer (WDT)

• Solution to ESP8266 wdt issue and "yield()" problem #73, Fix yield for ESP8266 #81, Change yield(); to delay(0); because esp8266 2.4.0-rc2 wdt resets. #86, soft WDT reset on Esp8266 #101, Replacing yield() by delay(1) | Solution #120

[amotl]

Update

Thank you so much for testing this on real iron. I will update the documentation reflecting your findings.

I've just updated the README to accordingly. Thanks again.

Also, we've added some things coming from #125 to work on giving users more choice on whether to wait for the HX711 chip or not when initializing the hardware.

[amotl]

Thanks for merging, @bogde. It was a pleasure.

[ClemensGruber]

I tested the lib succesful with an:

• Adafruit HUZZAH ESP8266
• Heltec WiFi Kit 32 (ESP32)
• Adafruit Feather HUZZAH32 (ESP32)

[amotl]

Thanks for testing on more hardware devices, @ClemensGruber! We just made #127 to account for that.

[amotl]

@thiasB also found that

Code is running fine on an Adafruit Feather M0 RFM95 Lora 1 (ATSAMD21G18 Cortex M0) board.

Thanks for testing!

[amotl]

While @riemers also confirms more stability with the changes coming from this PR, he reports about random erratic readings when running on ESP8266.

While he outlined his observations at Skaronator/ESP8266-Load-Cell#8 (comment), we might want to open a dedicated issue for that here.